Drilling control device

ABSTRACT

A drilling control device for inclusion in a drill string and serving in place of a short section thereof, embodying an internal bore closure member for closing off the internal well bore in response to sub-surface high-pressure conditions which may be encountered during drilling operations, and a well bore closure member in the form of a normally contracted, expansible packing ring which is expansible in response to the application of fluid pressure thereto from a fluid pressure system operable by the internal bore closure member to seal off the annular space between the drilling control device and the well bore.

[ Jan. 22, 197 1 DRILLING CONTROL DEVICE [76] lnventor: August L. Segelhorst, 211 Las Alturas Rd., Santa Barbara, Calif. 93103 [22] Filed: Mar. 15, 1972 [21] Appl. No.: 234,707

[56] References Cited UNITED STATES PATENTS 11/1966 Warrington 166/187 9/1971 Malone 166/187 3,134,441 5/1964 Barry et al.... 166/187 3,351,349 11/1967 Chenoweth... 166/187 3,529,665 9/1970 Malone 166/187 3,575,237 4/1971 Malone 166/187 Primary Examiner-James A. Leppink Attorney, Agent, or F irm-Whann & McManigal [5 7] ABSTRACT A drilling control device for inclusion in a drill string and serving in place of a short section thereof, embodying an internal bore closure member for closing off the internal well bore in response to sub-surface high-pressure conditions which may be encountered during drilling operations, and a well bore closure member in the form of a normally contracted, expansible packing ring which is expansible in response to the application of fluid pressure thereto from a fluid pressure system operable by the internal bore closure member to seal off the annular space between the drilling control device and the well bore.

9 Claims, 3 Drawing Figures DRILLING common. DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention has to do generally with devices used to control the escape of fluids under pressure from oil wells, and more particularly to devices designed for use under emergency or unusual conditions when temporary shutting in of the well is considered necessary as, for example, when high-pressure sands or other subsurface high-pressure conditions are encountered while drilling.

2- Pissessiqa ttlta lmrA2.

Applicant is familiar with the following related prior art patents, none of which disclose nor remotely suggest applicants novel device as described herein:

U.S. Pat. No. 2,458,270 Humason U.S. Pat. No. 2,783,028 -Jamison, .Ir.

U.S. Pat. No. 2,978,046 True U.S. Pat. No. 3,283,823 -Warrington U.S. Pat. No. 3,367,422 -Sims SUMMARY OF THE INVENTION It is a major object of my invention to provide a novel drilling control device for automatically closing off oil or gas wells in the event that sub-surface high-pressure conditions likely to cause a well blowout are encountered during drilling operations.

It is another object of my invention to provide a drilling control device of the type described in the preceding paragraph which can be easily interconnected into a drill string and which will in no way interfere with normal well drilling operations.

It is still another object of my invention to provide a drilling control device which embodies separate but cooperatively associated sealing members for closing off the internal bore of the drill string in response to fluids flowing upwardly through the drill string, and for simultaneously and automatically closing off the annular space between the drill string and the well bore.

It is a further object of my invention to provide a drilling control device of the type described in the preceding paragraphs in which the sealing member for closing off the space between the drill string and the well bore comprises a normally contracted expansible packing ring carried by the device which is expansible in response to fluid under pressure supplied by a selfcontained fluid control system which is operable by the internal bore closure means.

It is still a further object of my invention to provide a drilling control device of the class described which contains its own supply of pressure fluid in a quantity sufficient to permit repeated automatic operation of the expansible packing ring without the necessity of repressurizing the device.

It is another object of my invention to provide a drilling control device of the class described in which cooperatively associated control and regulator valves for automatically controlling the flow of fluids within the fluid system of the device are housed within the device and require no connection with the surface of the ground.

It is still another object of my invention to provide a drilling control device in which the fluid system can be quickly and efficiently repressurized without the necessity of removing the device from the drill string.

In summary, these and other objects of my invention are achieved by my novel drilling control device which includes a body adapted for interconnection in a drill string, said body having a bore therethrough arranged for communication with the axial bore of the drill string, an internal bore closure member for closing off the bore through the body in response to fluid pressures opposing the normal flow of drilling fluid through the drill string, and a well bore closure member operable by the internal bore closure member for closing off the annular space between the device and the well bore.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view, in section, of the drilling control device of my invention as it appears in operative position within a well bore.

FIG. 2 is an enlarged fragmentary view of the lower portion of the drilling control device illustrating the operation of the internal bore closure means and showing the arrangement of the control valve and regulator valve means of the invention.

FIG. 3 is a cross-sectional view taken along line 33 of FIG. 2 illustrating the configurationof the internal bore closure means of my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 of the drawings, a well bore 12 is shown extending into the earth 14. The reference numeral 16 generally designates the drilling control device of my invention as it appears in operative position within the well bore. Drilling control device 16 is shown in this form of my invention as a complete assembly which can be interconnected into a conventional drill string (not shown) of the type typically used for earth drilling having an axial bore through which drilling fluid flows during drilling operations.

As shown in FIG. 1, the drilling control device 16 comprises a generally tubular body 18 having a bore 20 therethrough. The upper end of body 18 is connected by suitable joint means to the lower end of a section of the drill string so as to depend downwardly in a fixed axial relationship therefrom with bore 20 in communication with the bore of the drill string. Although for certain applications the lower end of body 18 may be connected to the upper end of another section of the drill string so as to suspend the control device imtermediate of the drill string, the lower end of body 18 is generally connected by suitable joint means to the upper end of the bottom hole assembly of the drill string which carries the drill bit.

Near the lower extremity of body 18 is a radially enlarged chamber or bore 22 which houses an internal bore closure means adapted to close off the axial bore 20 through body 18 in response to fluid pressures opposing the normal flow of drilling fluid through the drill string. The internal bore closure means is shown in this form of my invention as comprising a flapper member 25 pivotally carried by body 18 and arranged to swingably move within chamber 22 into a position sealably closing the bore through body 18.

Referring to FIG. 3, it can be seen that chamber 22 is irregular in cross-sectional shape having a generally vertical, transversely extending flat wall portion 28 against which flapper 2S rests when it is in its open position. Near the upper end of chamber 11 I provide a transversely extending pivot bar 30 adapted to pivotally carry flapper member 25.

Pivot bar 30 extends through a transverse bore formed in a marginal extension 31 of the flapper member and has both of its ends supported by the walls of body 18 so that it forms a rigid axis about which the flapper member can pivot within chamber 22 into an open and closed position.

The upper surface of flapper member 25 carries a sealing means in the form of an eccentrically shaped sealing disc 32 for sealably engaging the shoulder 34 formed at the juncture of bore and chamber 22. Disc 32 may be constructed of any suitable yieldable sealing material such as, for example, copper, soft aluminum, hard rubber or plastic, and serves to prevent the upward flow of fluids through bore 20 when the flapper member is in a closed position.

Referring now to FIGS. 1 and 2, it can be seen that when the flapper member is in its normal, at rest position, it is yieldably held in a spaced relationship with wall 28 of chamber 22 by a spring means provided in the form of an outwardly bowed spring member 36 which is affixed to the lower surface of flapper member 25. So that the flapper member in its at rest position will not interfere with tooling, piping or other objects which may be inserted downwardly through the drill string, spring member 36 is constructed so that downward pressures exerted against the flapper member will cause the spring to compress, allowing the flapper member to move out of the way and into a parallel relationship with wall 28. To assist the tooling or piping in moving the flapper member out of the way an outwardly extending hump-like portion 37 is formed on the surface of the flapper opposite spring member 36.

As is best seen in FIG. 1, there is formed in the lower portion of wall 38 of body 18 a bypass means 40 for directing drilling fluid against the lower side of the flapper member so as to urge it, in response to fluid pressures opposing the normal downward flow of drilling fluid through the drill string, to swingably move into the position shown in FIG. 2, closing the bore 20 through body 18. To facilitate forming the bypass means, wall 38 is provided with a radial bore 42 which permits the drilling of upwardly and downwardly extending fluid passageways 44 and 46 through wall 38. After the drilling of wall 38 has been completed a plug 48, which has been suitably drilled to form internal bores which will correctly register with passageways 44 and 46, is inserted into bore 42 and affixed to body 18 in any suitable manner such as by welding. To complete bypass means 40, an insert 50, which has an axial bore 52 aligned with bore 20 in body 18 and an upwardly extending fluid passageway 54 arranged so as to register with passageway 46, is inserted into the lower end of chamber 22 and is affixed to body 18 as by welding. As shown in FIG. 1, bypass 40 is positioned relative to flapper member 25 so that fluids passing upwardly through the bypass will impinge directly upon the lower surface of the flapper member, causing it to swingably move from an open position, as indicated by the phantom lines in FIG. 2, into a closed position, as indicated by the solid lines in FIG. 2.

It will be appreciated that the bypass means can be formed in a variety of ways only one of which has been described herein. For example, plug 50 can be affixed in place within chamber 20 and then the fluid passageway 54 drilled. Alternately, if desired, chamber 22 and bore 52 can be formed within a one piece body 18 so as to completely eliminate the requirement for a separate plug 50. The manner in which chamber 22 and the bypass means are formed and their specific configurations may vary depending upon the particular application of the device of my invention and I do not intend to be limited to the precise configuration shown in the drawings.

Formed intermediate the ends of body 18 are sections of reduced outside diameter, identified by the numerals and 62. As shown in FIG. 1, these sections are divided by a web section 64 which is designed to structurally support pressure chamber wall means 65 provided here in the form of a generally cylindrically shaped tubular casing member 66. Member 66 is of the same outside diameter as body 18 and, when welded in place to body 18 at locations 67 as shown in FIG. 1, serves to form closed pressure chambers 70 and 72 within body 18. Web section 64 is provided with an annular opening 74 which serves to interconnect pressure chambers 70 and 72 so as to permit fluid flow therebetween.

Pressure chambers 70 and 72 are adapted to contain fluids such as inert gases under high pressure and can be pressurized by means of a pressure chamber valve means, identified in FIG. 1 by the numeral 77. Valve means 77 is mounted within a radial bore 82 formed in the wall of body 18 immediately adjacent pressure chamber 72 and includes a valve body which is threadably received within bore 82. Body 80 is sealed relative to body 18 by an O-ring 83 and is provided with an internal chamber 84 adapted to house a ball 86 which is normally held against an internal seat by means of a spring 90 in a manner as to close an inlet passageway 91 formed in the valve body. As can be seen in FIG. 1, with valve body 80 sealably in position within body 18, chamber 84 is in communication with pressure chamber 72 through passageways 92 and .94 formed in body 80 and wall 38 respectively. A plug 96 which sealably closes inlet passageway 91 is threadably received within valve body 80 and is sealed relative thereto by an O-ring 98.

Supported near the upper end of body 18 is a well bore closure means operable by the internal bore closure means for closing off the annular space between the well control device and the well bore. The well bore closure means of this form of my invention comprises a normally contracted expansible packing ring means 100 which is expansible outwardly in response to the application of fluid pressure thereto. Packing ring means 100 is carried within an annular groove 102 formed in the upper portion of wall 38 of body 18 and may be constructed of any suitably flexible yet durable rubber or plastic material.

The packing ring is provided with an annular groove in communication with a source of fluid under pressure and is designed so that when it is expanded outwardly in response to fluid pressure, its outer periphery will conform to, and effectively seal, against the well casing of the well 103 as shown on the left side of FIG. 1, or, if the well is not yet cased, against the earth itself as illustrated on the right side of FIG. 1.

Conduit means, generally designated by the numeral 104, is provided in wall 38 of body 18 so as to form a pressure fluid passageway from pressure chambers 70 and 72 to the packing ring. The conduit means of my invention comprises a generally vertically extending upper passageway 106 and a communicating radially enlarged generally vertically extending lower passageway or bore 108. Housed within bore 100 is a valve means 110 which forms a part of the fluid control means of my invention. This fluid control means, which also includes a regulator valve means presently to be described, is operable by the internal bore closure means and performs the important function of controlling the flow of fluid from the pressure chambers through the conduit means to the well bore closure means. Control valve means 110 is designed to control the flow of fluid into the conduit means and comprises a generally cylindrically shaped body portion 112 which is adapted for telescopic movement within chamber 108. An O-ring 1 13 provides means for sealing body 112 as it moves within chamber 108. Formed within body portion 112 is a vertically extending passageway 114 and upper and lower transversely extending passageways 116 and 118 respectively. Affixed at the lower end of body portion 112 is a depending generally rectangularly shaped rod or plunger 120 which protrudes through an axial bore formed in a plug 124 which is threadably received in the lower end of bore 108. Rod 120 serves to align body 112 within bore 100 and extends downwardly into chamber 22 of body 18 where it is engageable by flapper member 25 of the internal bore closure means when the latter member swings into a closed position. A biasing means in the form of a spring 126 is disposed within bore 100 and is adapted to hold body 112 normally against plug 124 with plunger 120 depending into chamber 22.

As can best be seen in FIG. 2, when flapper member 25 swingably moves into a closed position as a result of encountering abnormal pressure conditions in the well which cause a reversal of flow of the drilling fluid, it engages plunger 120 moving body 112 upwardly within bore 108 against the urging of spring 126. When, as shown in FIG. 2, the flapper member is fully closed, sealing bore 20 against the upward flow of fluids through the drill string, body 112 of control valve means 110 is moved to a position wherein upper transverse passageway 116 is in alignment with a transverse bore 128 which interconnects pressure chamber 72 and chamber 108 of conduit means 104. In this position fluids may flow from the pressure chambers through the conduit means to the packing ring means, causing the expansible ring to expand outwardly in a manner as to seal the annular space between the control device and the well bore against the upward flow of fluids through the well.

When well conditions return to normal and the flapper member again returns to its normal open or downwardly depending position due to gravity or the downward pressure of the drilling fluid, spring 126 will urge body 112 of the valve control means downwardly into a seating position against plug 124. In this position lower passageway 118 is in alignment with a venting passageway 130 which interconnects bore 20 of body with chamber 108 of the fluid control device, thereby allowing fluids under pressure in the conduit means or packing ring to vent into the drill string. Where desired a check valve or other suitable valving means (not shown) may be incorporated into body 112, to permit venting, but to preclude the back flow of mud into the fluid passageways.

In order that I may pressurize the pressure chambers to high pressures, but at the same time limit the pressure to which the packing ring is exposed, I also provide as a part of the fluid control means of my invention a regulator valve means 132. Regulator valve means 132 is cooperatively associated with control valve means and, when the flapper member is in a closed position, serves to regulate the flow of fluid from the pressure chambers into the valve control means and then through the conduit means to the packing ring means.

In the form of my invention illustrated in the drawings, I show the regulator means 132 mounted within pressure chamber 72. While this construction is not absolutely essential, it has the advantage of protecting the regulator means from damage while at the same time increasing the compactness and reliability of the well control device.

The purpose of the regulator means is twofold. First, to provide a mechanism whereby the fluid pressure in the pressure chambers, which may be on the order of several thousand pounds per square inch, can be reduced to on the order of several hundred pounds so as to permit safe operation of the lower pressure packing ring system.

Secondly, the regulator means serves to maintain a constant pressure at the inlet to the valve control means so that a constant pressure will in turn be maintained on the packing rings when the flapper member is in a closed position and the valve control means is in an open position. With the arrangement shown and described, the well control device of my invention can be operated through several complete cycles without requiring repressurization of the pressure chambers.

It will be appreciated that numerous types of commercially available pressure control regulators can satisfactorily be used to regulate the flow of fluids to the control valve means of my device. Since the construction and operation of pressure regulators of a class adequate to perform the described function are well known in the art and form no part of my invention, I have diagrammatically illustrated a simple diaphragmtype regulator means. It is not intended, however, that I be limited to the construction of the regulator depicted in the drawings or to the description of its operation which follows.

Referring particularly to FIG. 2, the regulator valve means comprises a housing 135 having a high-pressure inlet port 137 which is normally open to the pressure chambers and a low-pressure outlet port 139 which is located so as to directly communicate with passageway 128 formed in wall 30 of body 10. Housing 135 is held in position within chamber 72 by means of a set screw 142 which is threadably disposed in wall means 66. Mounted within housing 135 is a diaphragm-operated valve means for controlling the flow of fluids from the high-pressure inlet port 137 to the low-pressure outlet port 139. An adjustable spring means 144 is arranged to act upon diaphragm 146 in a manner so as to urge the valve means into an open position when the pressure within the outlet side of housing 135 falls below a predetermined level. As long, however, as the pressure acting upon the diaphragm within the outlet side of the housing equals or exceeds the opposing pressure exerted on the diaphragm by spring means 144, the valve will remain closed and fluid cannot flow from the pressure chambers into the outlet side of the housing. To prevent leakage of fluids from the pressure chamber into the conduit means, an ()-ring is provided between the outlet port of the valve and passageway 128.

OPERATION In constructing the well control device of my invention, the regulator valve means, having first been adjusted to provide the desired fluid pressure at its outlet side, is positioned within pressure chamber 72 and then wall means 66 is welded in place so as to form the sealed pressure chambers 70 and 72. The pressure chambers can be initially pressurized through pressure chamber valve means 77, or, if desired, the device can be interconnected into the drill string prior to pressurizing the chambers. I have found that when using an inert gas such as, for example, nitrogen as the pressurizing fluid, the pressure chambers can be pressurized to on the order of 6,000 to 7,000 psi. With this pressurization of the chambers if the regulator valve means is set to provide a pressure at the outlet port of, for example, on the order of 1,200 to 1,300 p.s.i., the device can be operated through several complete well closure cycles without the necessity of again pressurizing the chambers.

Pressurizing the chambers is readily accomplished by first removing plug 96 of pressure chamber valve means 77 and then inserting a probe connected to a nitrogen pressure line into inlet 91 in a manner so as to displace ball 86 from its seat, thereby allowing the gas to flow through the probe into the pressure chambers through passageways 92 and 94. When the probe is removed, ball 86 will return to its seat due to the urging of spring 90, thereby sealing inlet 91 against the leakage of gases from the pressure chambers.

With the well control device interconnected in the drill string and the pressure chambers appropriately pressurized, drilling can proceed in a normal manner with drilling fluid passing downwardly through the drill string and through bore of body 18. In the event that the drill bit encounters high-pressure sands or other sub-surface pressure conditions likely to cause blowout and a concomitant reversal of the normal downward flow of the drilling fluid, a portion of the upwardly flowing fluids will of necessity enter bypass 40 where it will be directed against the lower side of flapper member 25. These fluids under pressure will cause the flapper member to pivot about bar and swing into a closed position, as illustrated in FIG. 2 of the drawings. This will seat sealing disc 32 against shoulder 34 so as to seal bore 20 against the upward passage of fluids and, at the same time, will cause plunger 120 and body 112 of the control valve means to move upwardly against the urging of spring 126 into a position wherein passageway 116 is aligned with passageway 128. As the control valve means 110 is moved into the position as described, the outlet side of the regulator valve means is opened to conduit means 104 through passageway 128, causing a pressure drop to occur on the outlet side of the valve. This drop in pressure results in a reduction of the pressure being exerted on diaphragm 136 thereby allowing spring 134 to move the valve into an open position and permitting fluid under pressure to flow to packing ring 100 of the well bore closure means. The packing ring in response to the fluid pressure will expand outwardly, sealing the annular space between the control device and the well bore. In this 6 way the well bore is completely and effectively sealed against an upward passage of fluids through the well.

When the fluid pressure within the packing ring, conduit means and outlet side of the regulator valve reaches a pressure sufficient to permit diaphragm 136 to move upwardly against the urging of spring 134, the regulator valve will return to a closed position, blocking further flow of fluids from the pressure chamber. Should a leak occur or should the assemblage shift so that additional fluid pressure is required to securely seat the packing ring, the resultant drop in pressure on the outlet side of the regulator valve will again cause the valve to open, permitting flow of fluids from the pressure chamber into the conduit means.

At such time as the down-hole pressures are relieved so as to once again permit the normal flow of drilling fluid through the drill string, flapper member 25 will swing automatically into its normal open position. This will in turn permit control valve means 1 10 to automatically move into a closed position due to the urging of spring 126. As the valve returns to its closed position, passageway 118 will align with venting port 130, permitting the fluids under pressure in the conduit means and the packing ring to vent into the drill string. In this configuration the well control device is again ready to repeat the well closure cycle should unexpected pressure conditions in the well be encountered.

I claim:

1. A drilling control device adapted to be connected into a drill string above the bottom hole assembly which mounts the drill bit for closing off the well in the event that sub-surface high-pressure conditions tending to oppose the normal downward flow of drilling fluid are encountered while drilling, comprising in combination:

a. a body having a bore therethrough in communication with the bore of the drill string;

b. an internal bore closure means for closing the bore through said body in the event that sub-surface high-pressure conditions are encountered;

c. normally contracted expansible packing ring means carried by said body and expansible in response to the application of fluid pressure thereto so as to close off the annular space between the drilling control device and the well bore; wall means forming a pressure chamber within said body;

e. conduit means passing through said body so as to provide a pressure fluid passage from said pressure chamber to said packing ring means; and

fluid control means operable by said internal bore closure means for controlling the flow of fluid from said pressure chamber through said conduit means to said packing ring means, said fluid control means comprising:

1. a normally closed control valve means operable by said internal bore closure means for permitting the flow of fluid from said pressure chamber through said conduit to said packing ring means when said closure means is in a closed position; and

2. a regulator valve means cooperatively associated with said control valve means for regulating the flow of fluid from said pressure chamber through said conduit means to said packing ring means. 2. The apparatus as defined in claim 1 in which said internal bore closure means comprises a flapper member mounted for pivotal movement within a radially enlarged chamber formed within said body adjacent to and in communication with the bore therethrough, said flapper member being adapted to swingably move into a position to sealably close the bore through said body.

3. The apparatus as defined in claim 2 including bypass means for directing drilling fluid against said flapper member so as to urge it in response to fluid pressures opposing the normal flow of drilling fluid through the drill string to swingably move into a position to sealably close the bore through said body.

4. The apparatus as defined in claim 2 including sealing means carried by said flapper member for sealably engaging the shoulder formed at the juncture of the internal bore in said body and the radially enlarged bore in said body so as to sealably close the internal bore.

5. The apparatus as defined in claim 2 including spring means for holding the free end of said flapper member normally in a spaced relationship with the vertical side walls of the radially enlarged chamber in said body, said spring means being compressible so as to allow the free end of said flapper member to be moved into juxtaposition with the vertical side walls of the radially enlarged chamber in said body by an object extending downwardly through the internal bore of said body.

6. The apparatus as defined in claim 2 in which said control valve means is operable in response to movement by said flapper member into a closed position so as to permit fluids to flow from said pressure chamber through said conduit means to said packing ring means.

7. The apparatus as defined in claim 6 including biasing means for holding said control valve means in a closed position, blocking the flow of fluids from said pressure chamber through said conduit means when said internal bore closure means is in an open position.

8. The apparatus defined in claim 7 including venting means for venting the fluid under pressure in said conduit means into the bore in said body when said control valve means is in a closed position.

9. A drilling control device adapted to be connected into a drill string above the bottom hole assembly which mounts the drill bit for closing off the well in the event that sub-surface high-pressure conditions tending to oppose the normal downward flow of drilling fluid are encountered while drilling, comprising in combination:

a. a body having a bore therethrough in communication with the bore of the drill string;

b. an internal bore closure means for closing the bore through said body in the event that sub-surface high-pressure conditions are encountered;

c. normally contracted expansible packing ring means carried by said body and expansible in response to the application of fluid pressure thereto so as to close off the annular space between the drilling control device and the well bore;

d. wall means forming a pressure chamber within said body;

e. conduit means passing through said body so as to provide a pressure fluid passage from said pressure chamber to said packing ring means;

f. fluid control means operable by said internal bore closure means for controlling the flow of fluid from said pressure chamber through said conduit means to said packing ring means; and

g. pressure chamber valve means carried by said body for permitting pressurization of said pressure chamber. 

1. A drilling control device adapted to be connected into a drill string above the bottom hole assembly which mounts the drill bit for closing off the well in the event that sub-surface high-pressure conditions tending to oppose the normal downward flow of drilling fluid are encountered while drilling, comprising in combination: a. a body having a bore therethrough in communication with the bore of the drill string; b. an internal bore closure means for closing the bore through said body in the event that sub-surface high-pressure conditions are encountered; c. normally contracted expansible packing ring means carried by said body and expansible in response to the application of fluid pressure thereto so as to close off the annular space between the drilling control device and the well bore; d. wall means forming a pressure chamber within said body; e. conduit means passing through said body so as to provide a pressure fluid passage from said pressure chamber to said packing ring means; and f. fluid control means operable by said internal bore closure means for controlling the flow of fluid from said pressure chamber through said conduit means to said packing ring means, said fluid control means comprising:
 1. a normally closed control valve means operable by said internal bore closure means for permitting the flow of fluid from said pressure chamber through said conduit to said packing ring means when said closure means is in a closed position; and
 2. a regulator valve means cooperatively associated with said control valve means for regulating the flow of fluid from said pressure chamber through said conDuit means to said packing ring means.
 2. a regulator valve means cooperatively associated with said control valve means for regulating the flow of fluid from said pressure chamber through said conDuit means to said packing ring means.
 2. The apparatus as defined in claim 1 in which said internal bore closure means comprises a flapper member mounted for pivotal movement within a radially enlarged chamber formed within said body adjacent to and in communication with the bore therethrough, said flapper member being adapted to swingably move into a position to sealably close the bore through said body.
 3. The apparatus as defined in claim 2 including bypass means for directing drilling fluid against said flapper member so as to urge it in response to fluid pressures opposing the normal flow of drilling fluid through the drill string to swingably move into a position to sealably close the bore through said body.
 4. The apparatus as defined in claim 2 including sealing means carried by said flapper member for sealably engaging the shoulder formed at the juncture of the internal bore in said body and the radially enlarged bore in said body so as to sealably close the internal bore.
 5. The apparatus as defined in claim 2 including spring means for holding the free end of said flapper member normally in a spaced relationship with the vertical side walls of the radially enlarged chamber in said body, said spring means being compressible so as to allow the free end of said flapper member to be moved into juxtaposition with the vertical side walls of the radially enlarged chamber in said body by an object extending downwardly through the internal bore of said body.
 6. The apparatus as defined in claim 2 in which said control valve means is operable in response to movement by said flapper member into a closed position so as to permit fluids to flow from said pressure chamber through said conduit means to said packing ring means.
 7. The apparatus as defined in claim 6 including biasing means for holding said control valve means in a closed position, blocking the flow of fluids from said pressure chamber through said conduit means when said internal bore closure means is in an open position.
 8. The apparatus defined in claim 7 including venting means for venting the fluid under pressure in said conduit means into the bore in said body when said control valve means is in a closed position.
 9. A drilling control device adapted to be connected into a drill string above the bottom hole assembly which mounts the drill bit for closing off the well in the event that sub-surface high-pressure conditions tending to oppose the normal downward flow of drilling fluid are encountered while drilling, comprising in combination: a. a body having a bore therethrough in communication with the bore of the drill string; b. an internal bore closure means for closing the bore through said body in the event that sub-surface high-pressure conditions are encountered; c. normally contracted expansible packing ring means carried by said body and expansible in response to the application of fluid pressure thereto so as to close off the annular space between the drilling control device and the well bore; d. wall means forming a pressure chamber within said body; e. conduit means passing through said body so as to provide a pressure fluid passage from said pressure chamber to said packing ring means; f. fluid control means operable by said internal bore closure means for controlling the flow of fluid from said pressure chamber through said conduit means to said packing ring means; and g. pressure chamber valve means carried by said body for permitting pressurization of said pressure chamber. 